Q:

4/23/2014
We recently evaluated a 5 month-old child who had anaphylaxis after ingestion of Enfamil formula. We assumed this was milk allergy, but we found soy listed as an ingredient on the Enfamil label. The ingredients list includes both vegetable oil (palm olein, coconut, soy, high oleic sunflower oils...) and soy lecithin. I have two questions:

1. Soy lecithin is not considered a problem for soy allergic patients, but I don't know about the vegetable oil ingredient. Is this also an oil w/ no significant protein making it safe for an allergic patient?

2. Usually we would advise soy formula for a milk allergic infant, but we might be limited in this case because of possible soy allergy. If we were to go to extensively hydrolyzed formula (eHF), what is the proper way of introducing eHF into the diet? Since over 90% of milk allergic kids can tolerate eHF, is it given at home, challenged in the clinic? Is there merit in skin testing w/ full strength eHF first? Or should we go directly to AA formula since the price difference does not seem to be great between AA formulas and eHF?

A:

Thank you for your inquiry.

I am referring your inquiry to Dr. Dan Atkins, who is a nationally recognized expert in food allergy in children. As soon as we receive Dr. Atkins' response, we will forward it to you.

Thank you again for your inquiry.

Sincerely,
Phil Lieberman, M.D.

We received a response from Dr. Dan Atkins regarding your inquiry. Thank you again for your inquiry and we hope this response is helpful to you.

Sincerely,
Phil Lieberman, M.D.

Response from Dr. Dan Atkins:
As suggested, a 5 month-old infant with an episode of anaphylaxis after the ingestion of Enfamil formula is considered milk allergic until proven otherwise. Confirming the diagnosis of milk allergy and checking for potential sensitization to milk and soy either through skin testing and/or serum food-specific IgE testing is helpful. In response to your specific questions:

1. The oils mentioned as potential ingredients are highly refined and not considered to contain adequate immunogenic protein to cause an allergic reaction in the vast majority of individuals. I could not find a report of palm olein allergy in the literature.

2. Although opinions vary, in an infant with a history of anaphylaxis to a cow's milk based formula, transition to an extensively hydrolyzed formula is a reasonable choice. Given that this family is likely concerned about potential reactions to any formula, I would skin test the child to the eHF we planned to use and, if negative, I would have the parent give the child the first feeding of formula in the office under observation. Seeing the negative skin test and being able to give the first feeding under observation is reassuring to the parent. I usually have the parent give the infant a relatively small amount initially (5 ml to 1/2 ounce or so) and the remainder of a normal portion 20 to 30 minutes later if the first dose is well tolerated. Observation for an hour afterward is reasonable. These initial feedings are done in the morning in case of an unanticipated reaction. If the skin test to the eHF is positive, using an AA formula is a logical consideration. In some instances, where the burden of formula cost is an issue, a soy formula can be used if there is no evidence of sensitization to soy through skin testing to a commercial soy extract and the soy formula to be used. I have seen infants with a negative skin test to a commercial soy extract that had large positive skin tests to a soy formula.

3. Two articles you might find interesting (with additional useful references) that address some of the questions you raise include:

a. Fleischer DM, et al. Primary prevention of allergic disease through nutritional intervention. J Allergy Clin Immunol: In Practice 2013;1:29-36.

b. Sicherer SH & Sampson HA. Food allergy: Epidemiology, pathogenesis, diagnosis and treatment. J Allergy Clin Immunol 2014;133:291-307.

Dan Atkins, MD

AAAAI - American Academy of Allergy Asthma & Immunology